AttributeError: 'CustomVM' object has no attribute 'vm' when attempting to install with default preseed

[Para Siva]

When executing sudo -u utah -i /usr/bin/run_utah_tests.py -p http://bazaar.launchpad.net/~psivaa/+junk/server/download/head:/preseed-20120718101702-5vm20tppsxduju34-9/preseed -i /home/sivatharman/iso/ubuntu/quantal-server-amd64.iso 'http://bazaar.launchpad.net/~psivaa/+junk/server/download/head:/master.run-20120718101702-5vm20tppsxduju34-7/master.run'

The following crash occurrs.

INFO: Installing client deb on machine
INFO: Provisioning VM
INFO: Loading VM
INFO: Creating custom virtual machine
INFO: Preparing kernel
INFO: Unpacking kernel from image
INFO: Preparing initrd
INFO: Unpacking initrd from image
INFO: Unpacking initrd
INFO: Copying ssh public key
INFO: Creating latecommand script
INFO: Setting up preseed
INFO: Removing machine addresses from ssh known_hosts file
INFO: Stopping VM
Traceback (most recent call last):
  File "/usr/bin/run_utah_tests.py", line 123, in <module>
    run_utah_tests()
  File "/usr/bin/run_utah_tests.py", line 109, in run_utah_tests
    function(args=args)
  File "/usr/share/utah/examples/run_install_test.py", line 108, in run_install_test
    machine.destroy()
  File "/usr/lib/python2.7/dist-packages/utah/provisioning/vm/libvirtvm.py", line 710, in destroy
    self.stop(force=True)
  File "/usr/lib/python2.7/dist-packages/utah/provisioning/vm/libvirtvm.py", line 114, in stop
    if self.vm.isActive() == 0:
AttributeError: 'CustomVM' object has no attribute 'vm'

[Max Brustkern (nuclearbob)]

I've proposed a merge to fix the shown exception here:
https://code.launchpad.net/~nuclearbob/utah/vm-teardown-fix/+merge/131082

The underlying issue is that the preseed contains a number of lines starting with {% block, which are currently being interpreted as duplicates of the same question by the preseed processing system. I'm discussing with the team how best to handle this.